An exceptional four-dimensional unitary Hecke Yang–Baxter operator

We construct an explicit 16 by 16 unitary Yang–Baxter operator in the exceptional Hecke class [exp(i pi/3), 1/2, 4]. Its spectral projection has both unnormalized partial traces equal to twice the identity, so the tensor-space representation induces the Markov trace and faithfully localizes the C(sl_3,6) Jones–Wenzl sequence. The paper proves that four is the minimum local dimension. This record includes the manuscript, compilable TeX source, three exact verification routes, negative tests, frozen output, checksums, provenance, and submission metadata.